The present invention generally relates to roller thumb wheels for electronic devices.
Many mobile electronic devices such as personal digital assistants, cell phones, and other wireless devices utilize various input means for allowing a user to select or execute functions upon the device. Such input means can include keyboards for entering alpha-numeric text, dedicated function buttons, directional keypad buttons and roller thumb wheels.
Roller thumb wheels are desirable since they permit single-handed operation of the device. In particular, the thumb wheel is placed at a position on the device such that the user can actuate the thumb wheel with a thumb while holding the device in the palm of their hand. The thumb wheel can be rolled to highlight an icon displayed on an LCD panel of the device; and depressed to select the highlighted icon. Roller thumb wheels can be positioned on a device for left or right handed operation, and they protrude from the device.
When the mobile device is accidentally dropped, the impact can occur at the protruding rolling thumb wheel. The impact force applied to the thumb wheel can damage an assembly the thumb wheel is attached to, rendering the mobile device unusable. More specifically, the impact force can cause the thumb wheel assembly to break off a printed circuit board or other device element to which it is attached.
There exists, therefore, a need for a thumb wheel that can absorb impact damaging loads and minimize damage to elements or assemblies to which it is coupled.
In a first aspect, the present invention provides a shock absorbing roller thumb wheel for actuating an electro-mechanical switch, comprising a hub for attachment to the switch, a resilient outer rim encircling the hub, and force dispersion spokes connecting the resilient outer rim to the hub, each force dispersion spoke having a predetermined length and cross-sectional shape for radially and laterally deforming in response to an impact force applied to the resilient outer rim.
In a second aspect, the present invention provides a mobile device comprising an LCD panel for displaying information and a shock absorbing roller thumb wheel for actuating an electro-mechanical switch and changing the display information on the LCD panel. The shock absorbing roller thumb wheel comprises a hub for attachment to the switch, a resilient outer rim encircling the hub, and force dispersion spokes for connecting the resilient outer rim to the hub, each force dispersion spoke having a predetermined length and cross-sectional shape for radially and laterally deforming in response to an impact force applied to the resilient rim.